Chain substituted cyanine dyes containing a carbonyl and thiocarbonyl group



Patented Feb. 10, 1948 CHAIN SUBSTITUTED CYANINE DYES CON- TAINING A CARBONYL AND THIOCAR- BONYL GROUP Alh'ed'W. Anish, .lohnson City, N. Y., assignor to General Aniline & Film Corporation, New York, N. Y., a. corporation of Delaware No Drawing. Application October 11, 1944, Serial No. 559,134

This invention relates to new compounds for sensitizing photographic silver-halide emulsions and to a method of preparing the same. More particularly, the invention relates to new chainsubstituted cyanine dye bases and salts thereof containing a carbonyl or thiocarbonyl group as a part of the chain substitution.

sensitizing dye bases of the polymethine series which are substituted at the central carbon atom of the polymethine chain by either a thienyl, alkyl, oxalkyl, halogen, aryl, aralkyl, or acyl group are the subjects of several patents. In all of these dyes, however, the substitutions at the central carbon atom of the polymethine chain do not enter into a resonance configuration so as to act as an auxochromic group.

An object of the present invention is to provide new chain-substituted cyanine dyes and salts thereof, containing a carbonyl or thiocarbonyl group as a part of the chain substitution.

A further object is to provide a photographic element comprising an emulsion sensitized with new chain-substituted cyanine dyes and salts, thereof, containing a carbonyl or thiocarbonyl group as a part of the chain substitution.

Other objects and advantages of this invention will become apparent by reference to the following specification in which its preferred details and embodiments are described.

This invention is based on the discovery that sensitizing dye bases of the polymethine series, having introduced in the alpha-carbon atom of the polymethine chain a carbonyl or thiocarbonyl group. are suitable for sensitizingphotographic emulsions. In particular, they are especially useful for sensitizing silver-chloride emul- SlOnS. sirable property makes the sensitizing dye bases applicable to the vari-contrast printing process. It is believed that the carbonyl or thiocarbonyl group enters into the resonance configuration, acting as one of the auxochromic groups.

The dye bases which may be used as such or in the form of their quaternary ammonium salts are prepared by condensing an omega acyl azole with a cyanine -dye intermediate, and are characterized by the following general formula:

' wherein R represents an alkyl, e. g., methyl,

. 8 Claims. (01.260-240) This latter unexpected and highly de-fl 2 phenyl', anthranyl, alkoxyaryl, e. g., methoxyphenyl, ethoxyphenyl, propoxyphenyl, methylenedioxyphenyl and the like e. g., methylenedioxybenzene, etc., aralkyl, e. g., benzyl, methylbenzyl, ethylbenzyl, propylbenzyl, etc., R1 represents an alkyl group, W represents a substituent, e. g., hydrogen, alkyl, alkoxy, aryl and aralkyl groups of the same value as R, W represents a substituent, e. g., hydrogen, alkyl and alkoxy of the same value as R, X and X are the same or different and represent oxygen, sulfur,

selenium or wherein R and R" are alkyl groups of the same values as R, and Y represents either oxygen or sulfur, and n represents an integer of from one to two.

The omega acyl azoles used in the preparation of the new dyes of the present invention are described in U. S. Patents 2,166,198; 2,323,504 and 2,233,873. These compounds consist. for the most part, of one or more ring systems in each azole nucleus, which azole nucleus contains a CH2CO- group directly attached to the nucleus, through the methylene radical. The benzthiae zole-2-pyruvic ethyl ester used in the preparation of the new dyes of the present invention is prepared according to the method of Borsche and Doeller, Liebigs Annalen des Chemie, vol. 537, pages 56-58, 1938. v

The methods for the preparation of the cyanine dye intermediates e. g., 2(B-acetanilido vinyl) cyclammonium quaternary salts are given in the literature. One general method consists of reacting a cyclammonium quaternary salt such as 2-methylene benzthiazole with an excess of diphenyl formamidine in acetic anhydride to give 2(p-acetani1ido vinyl) benzthiazole.

Typical cyanine dye intermediates which can be employed. in the condensation reaction with an omega. acyl azole include: 2(p-acetanilido vinyl) cyclammonium quaternary salt, 2(5- anilino-p-ethyl-vinyl) cyclammonium quaternary salt, 2(4-acetanilido butadienyl) cyclammonium quaternary salt, 2(p-ethylmercapto) cyclammonium quaternary salt and 2(p-ethylmercapto-pethyl-vinyl) cyclammonium salt.

In preparing the novel sensitizing dyes of the 7 present invention, 1 mol of an omega acyl azole is heated with 1 mol of a cyanine dye intermediate under reflux conditions in the presence of a basic (acid binding) condensing agent such as pyridine, methyl pyridine, dimethyl pyridine, ethyl pyridine, ethylmethyl pyridine, trimethyl pyridine, quinoline and the like, using basic catalysts such as, triethyl amine or potassium carbonate, or in the presence of an acid condensing agent such as acetic acid or acetic anhydride, etc. Thesecondensing agents as such act as solvents for the reactants and as catalytic. condensing or binding agents. In general, the amount of condensing agent used may varywithin wide limits, e. 'g., from 1 to 25' mol's. Gon-- centrations ranging from about 1 mol to about mols are preferred.

The resulting product obtained; by condensing, an omega acyl azole with a cyanine dye intermediate may be, if desired, quaternizedaccording to well-known methods to give a dye salt. The dye:

salt thus obtained is readily converted into a different salt by treating it in solution with an,

aqueous solution of a salt containing the desired anion suchas, for. example, potassium bromide or iodide.

The following examples describe in detail the methods for accomplishing the above objects, but it is to be understood/that: they are inserted mere- 1y for the purpose of illustrations; and arenot to be construed asrlimiting the scope of the invention.

EXAMPLE: I-

'idene) propenyl] benzthiazole y 2.3: gms. of 2(p-acetanilido vinyl) benzthiazole ethiodide and; L3 gms. of, 2-phenacyl-benzthiazol were dissolved in 20.0cc. or drypyridine and 0.5 cc; of'triethylamine addedi The; mixture was refluxed for' 1 hours; than water added tomake it slightly cloudy; The; crystals: which. separated out" were washed with water." andv alcohol and finally boiled outwith ethyl: alcohol.

The dye sensitized a chloride emulsion rather strongly and a bromide emulsionlweaklya The alcohol solution of the intermediate had an absorption maximum at. about: 500 m l. An. alcohol solution of 25 mg. of the dye was-incorporated in- 1 kilogram of silver chloridev emulsion containing a small amount ofisilver bromide and having a total. content of 4-5% silver-halide; The dye imparts a sensitivity to about 600: ml, with a maximum sensitivity at about-550sm which is flat.

EXAMPLE 'II 2'- [.-1 -acetyl-3.- 3-ethyl-2( 3) -benzothiaaolylidene) propenyll benzthiazole Four and: one-half. arms. of: 2(p-acetanilido vinyl) benzthiazoleethiodide and 1.6gms. of 2;- acetonyl benzthiazole were dissolved in 40.0 cc. of dry pyridine to which 1.0 cc. of triethylamine had been added. The mixture was heated at 100 C. for 2 hours, while still warm 40cc. of water were added and after standing: dye crystals separated. The dye base wasnltered iii-81 d 4 washedwith dilute alcohol. It was. turther purifled by boiling out witnethyl alcohol. The alcohol solution of the intermediate had an absorption maximum at about 510 m An i alcohol solution of 30 mg. of the dye was incorporated in 1 kilogram of silver chloride emulsion containing a small amount of silver bromide and havingatotalcontent of 45% silver-halide. The dye. imparts asensitivity to about 600 m l, with a maximum; sensitivity at about 560 m which is flat- EXAMPLE III 2- [1-acetyl-5- 3-ethyl-2 (3) -benzothiazolylidene- LS-pentadienyl] benzthiazole 0.9 gm. of A acetanilidobutadienyl benzthiazole ethiodid and 0.9 gm. of.2-acetonyl benzthiazolewere dissolvedin. 15.0 cc. of dry pyridine and 0.5- cc. of triethylamine; added. The mixture stood atroom temperature for 3 to 4 hours- The reaction. was then completed by heating at 50450? C. for 2 hours. The dye. was-precipitated with water and. filtered: after standing another 3-4 hours- The filter. residuewas takenv upin dioxane and diluted with ethyl alcohoL- The pure dye separated on standing. The dye sensitized a ch10- rideemulsion rather strongly and abromide emulsion weakly. a

The alcohol solution of the dye. had an absorption maximum at about 560. m An alcohol solution of 40 mg. of the dye. was incorporated in 1 kilogram ofsilver chloride. emulsion containinga small amount of silver bromide and having a total contentof 4-5% silver-halide. The dyeimpartsasensitivity to. about 680m i, with a maximum sensitivity at about 630 mu, which is flat.

EXAMPLE IV 2- [1- (4') -methozrybeneoylv -3- 3-ethyZ-2 (-3) -benzothiazolylidene). propenyl] benzthiazole kilogram of silver chloride emulsion containing asmall amount of silver bromide and having a total content of 4-5% silver-halide. The dye imparts 9. Sensitivity to about 600 m with a maximum sensitivity at about 540 ml, which is flat.

EXAMPLE V 2-[1-(3,4) methylenedioxybenzoyl 3- (3 ethyl- 2(3)-benzothiazolylidene) propenyll benzthiazole 0.5 gm. of ZQB-acetanilido vinyl) benzthiazole ethiodide and 0.3 gm. of 3,4 methylenedioxyben- 'zoyl ethyl acetate were dissolved in 10.0 cc. of

dry pyridine and 0.25 cc. of triethylamine added. u

The mixture was refluxed 10-15 minutes, cooled and water added. After standing for several hours, crystals separated out. The crude dye was recrystallized from ethyl alcohol in two fractions. The pure dye was contained in the more insoluble fraction.

The alcohol solution of the dye had an absorp EXAMPLE VI 2- [1-acetyl-3- (3-ethyl-2 (3) -benzothz'azolylidene) propenyl] ben zoxazole 4.5 gms. of 2(p-acetanilido vinyl) benzthiazole ethiodide and 2.0 gms. of 2-.acetonyl benzoxazole were dissolved in cc. of dry pyridine and 1.0 cc. of triethylamine added. The mixture was refluxed for 20 minutes and then diluted with water. 'The' crystals which separated'out were filtered off, washed .with waterand recrystallized in two fractions from ethyl alcohol.

The alcohol solution of the dye had an absorption maximum at about 500 ma. An alcohol solution of 40 mg. of the dye was incorporated in 1 kilogram of silver chloride emulsion containing a small amount of silver bromide and having a total content of 4-5% silver-halide. The dye imparts a sensitivity to about 600 m with a maximum sensitivity at about 540 mu, which is Exaurru v11 7 2-[1-acet1/l-3-(3-ethyZ- 5,6-dimethyl 2(3) -benzoxaaolylidene) propenyl] benzthiazole CHa c-d=oB-o11=0 O 2.0 gms. of 2-acetonyl benzthiazole, and 5.0 ms. of 2(p-acetanilido vinyl) 5,6-dimethyl benzoxazole ethiodide were dissolved in 30.0 cc. of dry pyridine and 2.0 cc. of triethylamine added. The mixture was refluxed 20 minutes and water added while still hot. On standing, crystals separated which were filtered off, washed with water and then recrystallized from methanol.

The alcohol solution of the dye had an absorption maximum at about 500 III/.4. An alcohol solution of 25 mg. of the dye was incorporated in 1 kilogram of silver chloride emulsion containing a small amount of silver bromide and having a total content of 45%, silver-halide. The dye imparts a. sensitivity to about 600 m l, with a maximum sensitivity at about 550 ma, which is flat.

ExAMPLE VIII 2- [1 -acetyZ-3- (3-ethyl-5-ethoxy-2(3) -benzselen azvlylidene) propenyl] benzthiazole 2.0 gm. of 2-acetonyl benzthiazole and 5.0 gins. of 2(p-acetanilido vinyl)-6-ethoxy-benzselenazole ethiodide were dissolved in 30.0 cc. of dry pyridine and 2.0 cc. of triethylamine added. The mixture was refluxed for 20 minutes and water added while still hot. The. crystals which separated on standing were filtered off, washed with water and recrystallized in two parts from methanol. v

The alcohol solution of the dye had an absorption maximum at about 590 my. An alcohol solution of 25 mg. or the dye was incorporated in 1 kilogram of silver chloride emulsion containing a small amount of silver bromide and having a total content of 4-5% silver-halide. The dye imparts a sensitivity to about 690 Ill 1., with a maximum sensitivity at about 640 ml, which is flat.

EXAMPLE IX 2- [1-acetyl-3- (aetnyz-s-methomy-zwi -benzothiazolylidene) propenyll benzthz'azole CzHi EXAMPLE X.

2'- ["1 -acetyZ'-3- (1 -ethyZ-3,3;'-trimethyl-2 (3) -indolenz'nylidene') propenyl] b'enztlz'z'azole CH1 CH3 can 5.0; girls. of 1'-ethyl-2-formylmethylene-3,3;5- trimethyl indolenine-anddl) gms. of 2-acetonyl benzthiazole were dissolved-in; 50:0 cc. of acetic anhydride. Themixture was heated. to 140 C. for 1 hour, cooled and diluted with acetic acid; The dye was precipitated from the acid solution with water and the dye crystals purified from methylalcohol.

The alcohol solution of thedye had an absorption maiximum at about 500' my. An alcohol solution of'40'mg, of the dye was incorporated in 1 kilogram of silver chloride: emulsion containing a smallamount oi-silver bromide and having a total content of 4-5% silver-halide. The dye imparts a sensitivity to about 560 m with a maximum sensitivity at about 530 ma, which is fiat.

EXAMPLE XI 3,3 -dz'ethyl-S-acetyltbenzthiocarbocyanine iodide lz s.

3.5 gms. of 2"-acetonyl'benzthiazole ethiodide wasmixed with 4.5 gms. of 2(c-acetanilido vinyl) benzthiazole ethiodide,'30.0" cc; of dry' pyridine and 1.0 cc. of triethylamine. The mixture was refluxed 20 minutes and'the dyeiprecipitated with water. Thedye crystals were filtered ofl and recrystallized from ethyltalcohol;

The alcohol solution of the dye salt had an absorption maximum at about 570m An alcohol solution of 30 mg; of the dye was incorporated in 1 kilogram of silver chloride emulsion containing asmall amount of silver bromide and having a total content of 4-5% silver-halide. The dye imparts a sensitivity to about 640 m l, with a maximum sensitivity at about 610 m;:., which is flat.

While the above example has been described particularly with reference to the preparation of, a dye base, itwill. be understood that the dye bases inthe: preceding and subsequent examples may alsobe transformed into dye salts by methods known to the; art. The, dye salts, however, show a bathochromic shift under the .same conditions of application; over the dye bases. from Whichthey areiderlyedl y EXAMPLE XII 2- [1 -etlroxalyl-3- (3-ethy l-2( 3) -benzothiaeolylidene): propenyl] benzthiazole S ZQOCaHr s 0 0/ 1 gram each of 2-pyruvic acid ethyl ester of benzthiazole and 2(p-acetanilido vinyl) benzthiazole ethiodide were mixed in 15.0 cc. of dry pyridine and 4-5 drops of, triethylamine added. The mixture was refluxed: on an oil bath for 30 minutes, cooled and water added until slightly cloudy. The filtered dye crystals were washed with water and recrystallized from ethyl alcohol.

The: alcohol solution of the dye had an absorption maximum at about 500m An alcohol solution of 40 mg. of the dye was incorporated in 1 kilogram of silver chloride emulsion containing a small amount of silver bromide and having a total content of 4-5% silver-halide. The dye imparts a sensitivitytoabout 590m with a maximum sensitivity at about 540 mp, which is flat.

ExAMPLaXlII COOCzHs Cans 1 grameacli-v of fl naphthiazole.2-pyruvic acid ethyl. ester: and zqi-acetanili'dovinyl) benzthiazole ethiodide were dissolved in 15.0 cc. of dry pyridine and 0.5 cc. of triethylamine added. The mixture was refluxed; for 30 minutes, cooled and diluted out with water. The crystals which separated were filtered and washed several times with alcohol and boiled out twice'with methanol.

The alcohol solution of the dye had an absorption maximum at about 500 m. An alcohol solution of 30. mg. of the dye was. incorporated in 1 kilogram of silver chloride emulsion containing a small amount of silver bromide and having a total content of 4-5% silver-halide. The dye imparts a sensitivity to about 600 m l, with a maximum sensitivity at about 500 me, which is flat.

EXAMPLE XIV- 2;-' ['1 '-thioacetyl-3;- (3-ethyl 2i(3) -benzothiazolylidene). propenyl]. benzthzazole One. gram of 2.-thioacetonyl1 benzthiazole, prepared by fusing 2-acetony1 benzthiazole with phosphorus pentasulfide at, C., was heated at.100 C. with 1.4 gms. of: 2-,8.-acetanilidc vinyl benzthiazole. in 10.0 cc; of dry pyridine and 1.0 cc. of triethylamine for 1 /2 hours. The reaction a small amount of silver bromide and having av total content of 4-5% silver-halide. The dye imparts a sensitivity to about 600 mg, with a maximum sensitivity at about 560 m which is flat.

In the preparation of emulsions containing these trinuclear cyanine dye bases and dyes, the base or dye may be dissolved in methyl or ethyl alcohol and avolume solution containing from 5 to 50 milligrams of the dye base or dye added to a liter of emulsion. While in general P ctice it may not be necessary to add the dye base or dye in the amounts larger than those above given, generally, for satisfactory results, amounts usually ranging from 5 to milligrams are sufficient to obtain the maximum sensitizing effect. However, I do not wish to limit my invention to a the quantities just indicated, the most suitable amount will in each case be found by a few comparative experiments. The dye bases or dyes may be added to the emulsions in form of solutions. Suitable solvents as indicated in the examples are the alcohols, for instance, methyl or ethyl alcohol, which may be anhydrous or diluted with a small volume of water. In actual practice, the dye bases and dyes are ap lied to the emulsion during any stage of its production, however, they are preferably added to the finished emulsion before being cast.

It will be understood that where in the claims appended hereto the term dye is used, that such is intended to include the dye salt.

While there have been pointed out above certain preferred embodiments of the invention, the same is not limited to the foregoing examples, illustrations, or to the specific details given therein, but is capable of variations and modifications as to the reactants, proportions and conditions employed. Accordingly, it is intended that the invention be defined only by the acing therein.

R f -Y i wherein R represents a member selected from oxyaryl radicals, R1 represents an alkyl group,

koxy, W' is a substituent selected from the class sisting of oxygen, sulfur and selenium, X represents a member selected from the class consisting of oxygen, sulfur, selenium and =C/ V RII where R and R" are alkyl radicals, Y represents a member selected from the class consisting of oxygen and sulfur and n is an integer of from one to two.

2. A cyanine dye of the following structure:

COOCzHs CzHa 3. A cyanine dye of the following structure:

O-OH2 CzHs 4. A cyanine dye of the following structure:

CH: S

5. A process of preparing a chain substituted cyanine dye containing a carbonyl group as the chain substituent which comprises refluxing in the presence of an acid binding agent, 1 mol of Z-pyruvic acid ethyl ester of benzthiazole with 1 mol of 2(p-acetanilido vinyl) benzthiazole ethiodide.

6. The process of preparing a chain substituted cyanine containing a carbonyl group as the chain substituent which comprises refluxing in the presence of an acid binding agent, 1 mol of 2(fl;acetanilido vinyl) benzthiazole ethiodide with 1 mol of 3,4 methylenedioxybenzoyl ethyl acetate.

7. A process of preparing a chain substituted cyanine containing a carbonyl group as the chain substituent which comprises refluxing in the presence of an acid binding agent, 1 mol of 2(c-acetanilido vinyl) benzthiazole ethiodide with 1 mol of 2-acetonyl benzthiazole ethiodide.

8. A process of preparing a chain substituted cyanine dye intermediate containing a member selected from the class consisting of carbonyl and thiocarbonyl groups as the chain substituent which comprises reacting an omega acyl azole of the general formula:

wherein R represents a member selected from the class consisting of alkyl, alkoxy, carboxyalkyl, aryl, aralkyl, alkoxyaryl and methylenedi- 11 oxyaryl radicals, W represents a substituent selected from the class consisting of hydrogen, alkyl, alkoxy, aryl and. aralkyl groups, X represents a member selected from the class consisting of oxygen, sulfurjand selenium, and Y represents a member selected from the class consisting, of oxygenvand sulfur, with a quaternary ammonium salt of aheterocyclic nitrogen compound of the type used in the preparation of cyanine dyes havinga' reactive group. selected from the class consisting of acetanilidovinyl, acetamlidobutadienyl, formylmethylene, anilido- B-ethyl vinyl, ethyl niercapto, and p-ethyl mer- 12 capto-fl-ethylvinyl; groups substituted in alphapositions to the ring nitrogen atom. thereof under the influence ofvheat in the presence of a basic condensing agent.

, ALFRED W.

REFERENCES CITED UNITED STATES; PATENTS Name Date Brooker Feb. 8, 1944 Number 

